This is a project to obtain immortalized nontumorigenic cell lines of human mesothelial and bronchial epithelial origin. Five lines have been established from normal human bronchial epithelial (NHBE) cells, one by infection with adenovirus 12-SV40 hybrid virus, two by infection with wild type SV40 virus, and two by transfection via strontium phosphate coprecipitation with a plasmid, pRSV-T, containing origin-minus SV40 early region sequences. One line has been established from normal mesothelial cells by transfection with the plasmid, pRSV-T. These cell lines are being used to study aspects of multistage carcinogenesis.